Method and apparatus for mass customized manufacturing

ABSTRACT

Embodiments of the invention provide a method and apparatus for manufacturing dental aligners. The system includes a workpiece introduction system having at least one workpiece preparation chamber. The system further has a mold manipulation system, having a mold introduction chamber, where a series of different molds may be introduced one after the other; a mold preparation chamber; a workpiece operation chamber; and a mold manipulator to move the mold between the mold introduction chamber, the mold preparation chamber, and the workpiece operation chamber; and a workpiece manipulator to move the workpiece between the workpiece preparation chamber and the workpiece operation chamber. In operation, the method includes steps of inserting a first workpiece into a workpiece preparation chamber; preparing the first workpiece for processing by subjecting the first workpiece to at least one preparation process; moving the first workpiece into a workpiece operation chamber; moving a first mold into a mold preparation chamber; preparing the first mold for processing by subjecting the first mold to at least one preparation process; moving the first mold into the workpiece operation chamber; moving the first mold and the first workpiece into cooperative engagement; subjecting the first workpiece to a vacuum on the side of the first workpiece facing the first mold; and repeating the above steps for a second workpiece and a second different mold.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a Continuation of co-pending application Ser. No.10/690,264, filed Oct. 21, 2003 the disclosure of which is incorporatedherein in its entirety.

BACKGROUND OF THE INTENTION

A. Field of the Invention

This invention relates to the manufacture of mass customized items, andmore particularly to automated manufacturing processes of the same.

B. Description of the Related Art

Traditional methods of dental mold making are well known, and includesuch methods and apparatuses as are described in U.S. Pat. No.6,497,574, assigned to the assignee of the present application andincorporated by reference herein its entirety.

In such systems, a dental “aligner”, for application to a patientsteeth, is made from a mold. A series of aligners is constructed whichare sequentially applied by the patient to their teeth and which resultover time in beneficial changes to the patient's dental structure. Theinitial mold is made from an impression of the patient's teeth and thesubsequent molds and aligners are made using software and a digitizationof the initial mold. As described in the patent incorporated byreference above, the initial mold may be constructed by forming animpression of the patient's dentition using a suitable impressionmaterial, such as alginate or polyvinylsiloxane (PVS). Impressions ofthe upper jaw typically include the teeth, the palate and gingivaltissue surrounding the teeth on the facial and lingual surfaces.Impressions of the lower jaw typically include the teeth and gingivaltissue surrounding the teeth on the facial and lingual surfaces. Plasteris then poured into the impression to form a relief of the dentalfeatures. The relief is a permanent, three-dimensional mold of thedentition and oral tissues.

Improved methods of mold making include rapid prototyping. Rapidprototyping is a technology that has developed in the last decade.Through the use of modern solid modeling CAD packages, combined withlaser systems and new materials, solid parts may now be generateddirectly from a computer model. Examples of this technology includestereo lithography (SLA), laminate object manufacturing (LOM), and fuseddeposition modeling (FDM), to name a few.

Stereolithography is a method that employs an ultraviolet laser to curea thin layer of liquid plastic into a solid. The process operates bytaking a thin layer of the light-sensitive liquid plastic and passingthe laser beam over the points where the part is solid. Once a pass iscompleted, another layer of the liquid is added to the existing part,and the process repeats until the full part height is achieved. SLAparts are extremely accurate, and tend to have excellent surfacefinishes. A variety of SLA materials are available for differentpurposes, including waxes, plastics, and flexible elastomers. Typically,an SLA process may produce some 20-25 molds in an hour.

Producing a dental mold with rapid prototyping methods requires the useof a computerized model or digital data set representing the dentalgeometry and tooth configuration. The model is used to guide the moldmaking process to produce a replica or relief of the computerized model.The resulting relief is a three-dimensional mold of the dentition. Thismethod of making dental molds is particularly applicable to situationsin which multiple molds must be produced. In this case, one computerizedmodel may be used to make a number of molds in an automated fashion. Inaddition, this method is applicable to situations in which a mold of atooth arrangement that differs from the patient's current tootharrangement is needed to be produced or molds of multiple tootharrangements that differ from each other and the patient need to beproduced. In either case, the computerized model of the patient's teethmay be manipulated to portray each new tooth arrangement and a mold maybe produced to reflect each successive arrangement. This may be repeatedany number of times to derive a number of molds with differing tootharrangements. Such techniques may speed production time and reduce costsby eliminating the need for repeated casting and artistic resetting ofteeth in traditional mold manufacturing.

Series of dental molds, such as those described above, maybe used in thegeneration of elastic repositioning appliances for a new type oforthodontic treatment being developed by Align Technology, Inc., SantaClara, Calif., assignee of the present application. Such appliances aregenerated by thermoforming a thin sheet of elastic material over a moldof a desired tooth arrangement to form a shell. The shell of the desiredtooth arrangement generally conforms to a patient's teeth but isslightly out of alignment with the initial tooth configuration.Placement of to the elastic positioner over the teeth applies controlledforces in specific locations to gradually move the teeth into thedesired configuration. Repetition of this process with successiveappliances comprising new configurations eventually moves the teeththrough a series of intermediate configurations to a final desiredconfiguration. For example, a new appliance with a slightly differentconfiguration may be worn for 20 days before replacement with the nextappliance in the sequence. A full description of an exemplary elasticpolymeric positioning appliance is described in U.S. Pat. No. 5,975,893,and in published PCT application WO 98/58596 which designates the UnitedStates and which is assigned to the assignee of the present invention.Both documents are incorporated by reference for all purposes.

To carry out such orthodontic treatment, a series of computer models ordigital data sets is generated, stored and utilized to fabricate aseries of representative dental molds. The fabrication of a series ofaligners from such a series of molds involves disposing the molds in athermoplastic fabrication machine to produce each aligner. Thefabrication machine usually relies on selectively hardening anon-hardened resin to produce the appliance or aligner. This fabricationof a series of aligners from such a series of molds requires asignificant amount of labor because each mold must be individuallyhand-inserted and manipulated in the thermoplastic fabrication machineto produce each aligner. This laborious process is operator-intensiveand slow as generally only a single workpiece may be fabricated at atime. Other mass-customized manufacturing processes are similarlylabor-intensive.

SUMMARY

In one aspect, the invention is directed to an apparatus to manufacturedental aligners, including a workpiece introduction system having atleast one workpiece preparation chamber. The system further has a moldmanipulation system, having a mold introduction chamber, where a seriesof different molds may be introduced one after the other; a moldpreparation chamber; a workpiece operation chamber; and a moldmanipulator to move the mold between the mold introduction chamber, themold preparation chamber, and the workpiece operation chamber; and aworkpiece manipulator to move the workpiece between the workpiecepreparation chamber and the workpiece operation chamber.

Implementations of the invention may include one or more of thefollowing. The workpiece introduction system may be an inline system ora rotary turret system. The mold manipulation system may be a rotaryturret system. The mold introduction chamber and the mold preparationchamber may be the same chamber. A clamp system may be included toconnect the workpiece to the workpiece manipulator. A cutter may beincluded, whereby an individual workpiece may be removed from a roll ofplastic. The workpiece preparation chamber and the mold preparationchamber may include an oven, which may have a preheater or a heater orboth. The mold manipulation system may include a plug manipulator tomove a plug into the workpiece operation chamber. The apparatus mayfurther include a laser-marking system to mark the workpiece followingits removal from the workpiece operation chamber, and a trimming system,such as a multiple-axis CNC system, and preferably a 5-axis one, to trimthe workpiece following its removal from the workpiece operationchamber.

In another aspect, the invention is directed towards a method ofmanufacturing a series of dental aligners. The method includes steps ofinserting a first workpiece into a workpiece preparation chamber;preparing the first workpiece for processing by subjecting the firstworkpiece to at least one preparation process; moving the firstworkpiece into a workpiece operation chamber; moving a first mold into amold preparation chamber; preparing the first mold for processing bysubjecting the first mold to at least one preparation process; movingthe first mold into the workpiece operation chamber; moving the firstmold and the first workpiece into cooperative engagement; subjecting thefirst workpiece to a vacuum on the side of the first workpiece facingthe first mold; and repeating the above steps for a second workpiece anda second different mold.

Implementations of the method may include one or more of the following.The preparation of the first or second workpiece mal include preheatingor heating the first or second workpiece, respectively. This heating mayoccur at a temperature of between about 525 and 595° F. The same is truefor the first or second mold. The method may further include moving aplug and the first workpiece into cooperative engagement. The method mayfurther include marking the workpiece, such as by a laser-markingdevice, or trimming the workpiece.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which illustrate embodiments of the present inventionand are not intended to be limiting:

FIG. 1 is a top schematic view of a first embodiment of an automatedmanufacturing apparatus constructed in accordance with the principles ofthe invention.

FIG. 2 is a top schematic view of a second embodiment of an automatedmanufacturing apparatus constructed in accordance with the principles ofthe invention.

FIGS. 3A-3L are stepwise schematic views showing an embodiment of amanufacturing method in accordance with the principles of the invention.

FIG. 4 shows a top schematic view of a third embodiment of an automatedmanufacturing apparatus constructed in accordance with the principles ofthe invention.

FIG. 5 shows a cross-sectional view of one embodiment of amass-customized manufacturing system.

FIG. 6 shows a process for performing mass-customization using themachine of FIG. 5.

FIG. 7 shows an exemplary dental appliance during manufacturing.

FIG. 8 shows an exemplary dental appliance during use.

DETAILED DESCRIPTION

Although hereinbelow are described what are at present considered thepreferred embodiments of the invention, it will be understood that theinvention can be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. The present embodimentsare, therefore, to be considered in all aspects as illustrative and notrestrictive. Accordingly, the invention is limited solely by the claimsappended hereto.

Tuning now to the drawings, in which similar reference characters denotesimilar elements throughout several views, FIG. 1 illustrates oneembodiment of a manufacturing apparatus constituting an embodiment ofthe invention. In particular, FIG. 1 shows a workpiece introductionsystem in which thermoplastic workpiece preparation and introduction areaccomplished via a rotary turret apparatus. A rotary “plastic” turret 12is in cooperative engagement with a mold manipulation system, here moldturret 14. The plastic turret 12 rotates about a plastic turret axis 44and the mold turret 14 rotates about a mold turret axis 46. In general,and as will be described in greater detail below, the plastic turret 12provides various preparatory functions for a plastic initiallysheet-shaped workpiece 71 (see FIG. 3) and the mold turret 14 providesthe shaping of the workpiece 71 into a formed or finished aligner usingthe mold.

The plastic turret 12 has various workpiece preparation chambers toperform sequential processing functions in a semi-continuous fashion.These chambers include a proximal loading chamber 18 for introduction ofworkpieces. In this chamber, each workpiece 71, which may have beenpreviously clamped to a cartridge or other clamping system or the liketo facilitate its convenient introduction and manipulation, is placed ona workpiece manipulator 41 for introduction into and manipulation withinthe plastic turret 12. The workpiece 71 then enters the rotary portionof the plastic turret 12 via a distal loading chamber 22. The plasticturret 12 rotates in the direction indicated by a plastic turretdirection of rotation 26, which moves the workpiece 71 into the nextprocessing chamber. The workpiece 71 may be heated via an oven 24, thesame including a preheater 28 and a heater 30. For example, thetemperature of the workpiece 71 may reach 525 to 595° F. in thepreheater 28 and about the same or higher in the heater 30. This heatingallows the workpiece 71 to become pliable and subject to formation via amold and plug.

After departure from the heater 30, the heated workpiece 71 enters theworkpiece operation chamber 32 of the mold turret 14. This position ofcooperative engagement with the workpiece operation chamber 32 isindicated in FIG. 1 by a reference numeral 34. There it cooperativelyengages a mold and plug, the function and operation of which isdescribed below. Once the heated plastic workpiece 71 is formed by themold and plug, the same enters an ejection chamber 20, where it may beseparated from the mold, marked and trimmed by a process furtherdescribed below. In particular, the ejection chamber 20 is generic for agroup of systems that may include further processing, marking, trimming,etc.

The mold turret 14 also has various chambers to perform variousfunctions, and rotates in the direction indicated by a mold turretdirection of rotation 49 to allow sequential processing in asemi-continuous fashion. These chambers include a mold-loading chamber36, a plug-loading chamber 38, the workpiece operation chamber 32, and amold-preheating chamber 40. The mold may be moved between these chambersvia a mold manipulator 43. The mold manipulator 43, which may have aactuator shape to accomplish up-and-down movements, may also be movedsuch that the mold is in cooperative engagement with a workpiece 71 inthe workpiece operation chamber 32. The details of the cooperativeengagement and fabrication process are described in greater detail belowwith regard to FIG. 3.

FIG. 2 is a top schematic view of a second embodiment of an automatedmanufacturing apparatus constricted in accordance with the principles ofthe invention. FIG. 2 shows an inline plastic workpiece preparationsystem 16 in cooperative engagement with the mold turret 14. As in FIG.1, in general, the inline plastic workpiece preparation system 16provides various preparatory functions for the workpiece 71 and the moldturret 14 performs the shaping of the workpiece 71 into a formed alignerusing a mold. The basic construction of the mold turret 14 in FIG. 2 issimilar to or the same as that of the mold turret 14 in FIG. 1, and thediscussion of the mold turret 14 is correspondingly the same as thatabove.

The inline plastic workpiece preparation system 16 has various chambersto perform various functions. An inline loading chamber 45 is providedin-line with an inline oven 50. The inline oven 50 may include an inlinepreheating chamber 47 and an inline heating chamber 48.

The inline system has certain advantages over the rotary system ofFIG. 1. For example, in the inline system, a roll of plastic may beconveniently employed to provide the basic workpiece material, and thisroll can be cut into individual workpieces 71 at any time during thefabrication process, including even after the workpiece 71 is formedinto a finished aligner 136. In this way, the system may take advantageof assembly line techniques and have each station require nearly thesame amount of time, such that each workpiece is worked seriatim. Bycontrast, in the rotary system, each workpiece 71 must be cut into anindividual piece, at the latest, by the time the workpiece 71 enterschamber 20.

Also shown in this embodiment, but which may also be in any otherembodiments, is a marking system 52 and a trimmer 54. The marking system52, such as a laser marking system, may be used to burn a predeterminedcode onto the workpiece 71. The predetermined code may be used toidentify the workpiece 71 during use, as it is important for the user tobe able to choose the appropriate aligner for use during the dentaltherapy. The predetermined code corresponds to the mold used to form thealigner, and is further correlated to the NC file created by the initialdigitization and software analysis of the patient's teeth.

The trimmer 54 removes the excess plastic from the aligner 136, and istypically a 5-axis CNC (computer-numerical-control) machine. Generally,a 5-axis machine is used although in some circumstances less may beemployed. The CNC machine reads data from the NC file corresponding tothe aligner, this NC file generated as noted above by the initialthree-dimensional digitization and subsequent software analysis.

After the plastic is trimmed, the mold is removed from the finishedworkpiece or aligner 136. This step generally requires humanintervention, as the removal process is particularly difficult toachieve via automation. However, in some instances, this may also beperformed. To assist in the removal, the mold and/or the aligner may bemade with a release agent so as to ease separation. Such release agentsmay be, e.g., soap, Teflon®, or silicon, or other similar agents.

In another implementation, as shown in FIG. 4, an inline plasticworkpiece preparation system 16 is used in combination with a modifiedmold turret 15. In the modified mold turret 15, a single chamber 39 isused for mold introduction and preparation and a mold manipulator 37transfers the mold from the chamber 39 to the workpiece operationchamber 35. This embodiment has the advantage of convenience andsimplicity. The remainder of the system may be as previously described.

In use, and also referring to FIGS. 3A-3L, which illustrate stepwiseschematic views showing an embodiment of a manufacturing method inaccordance with the principles of the invention, a plastic sheet from aroll 58 may emerge through a set of rollers 62 (FIG. 3 A, step 64), theplastic sheet later to be cut by a cutter 60. After cutting, the cutsheet, now termed a “workpiece 71”, is grasped by a set of clamps orclamping system 76 so that the workpiece 71 may be held securely forfurther processing (FIG. 3B, step 66). Following clamping, the workpiece71 may be subjected to preheating by an oven 50 (FIG. 3C, step 68). Theheating allows the workpiece 71 to be made more pliable and thus easierto work.

Following preheating, the workpiece 71 is moved into a workpieceoperation chamber 32 via a workpiece manipulator such as is shown inFIG. 1. The workpiece operation chamber 32 includes two holes such thattwo opposing actuators may pass therethrough. A mold actuator 88 isemployed to support a mold 90 and a plug actuator 102 is employed tosupport a plug 104. The mold actuator 88 may be integral with the moldmanipulator 43 or they may be entirely separate systems.

The workpiece 71 is moved into proximity of the mold 90 (FIG. 3D, step70) and the plug 104 (FIG. 3E, step 72), see FIG. 3G, step 108. Aseparate heater 98 may be employed to preheat each of the mold 90 andthe plug 104 (FIG. 3F, step 74). The workpiece operation chamber 32 maybe heated such that the workpiece 71 becomes even more flexible andpliable (FIG. 3H, step 110). The mold 90 and the plug 104 may be broughtinto cooperative engagement by action of the mold actuator 88 and theplug actuator 102 (FIG. 3I, step 112). The plug 104 helps to ensure thatthe plastic of the workpiece is pulled over the mold. A vacuum may thenbe brought to bear on the workpiece 71, on the side of the workpiece 71opposite that of the plug 104, such that the workpiece 71 achieves aneven greater and tighter fit to the mold 90 (FIG. 3J, step 114). Afterthe workpiece 71 has achieved the same shape as the mold 90, the moldactuator 88 and the plug actuator 102 may be separated, at which pointthe mold 90 may be separated from the mold actuator 88 and may fitwithin the formed workpiece (FIG. 3K, step 116). The mold 90 may beseparated from the workpiece 71 by the action of an air actuator (FIG.3L, step 118). The clamps 76 may be removed.

The finished workpiece, now an aligner 136, may be marked foridentification as described above and trimmed to remove excess plasticalso as described above. The aligners or appliances will be marked insome manner, typically by sequential numbering directly on theappliances or on tags, pouches, or other items which are affixed to orwhich enclose each appliance, to indicate their order of use.Optionally, written instructions may accompany the system which setforth that the patient is to wear the individual appliances in the ordermarked on the appliances or elsewhere in the packaging. Use of theappliances in such a manner will reposition the patient's teethprogressively toward the final tooth arrangement.

FIG. 5 shows a cross-sectional view of one embodiment of amass-customized manufacturing system, while FIG. 6 shows a process forperforming mass-customization using the machine of FIG. 5. In theimplementation of FIG. 5, the apparatus for fabricating amass-customized appliance includes a web feeder; a load station coupledto the web feeder to receive a mold; and a forming station coupled tothe load station to generate the appliance. A programmable logiccontroller (PLC) is used to control the forming station. The PLCcontrols electrical and pneumatic I/O for the web feeder, heat zone,rotary SLA feed, forming, machine vision and die cutting functions. ThePLC stores and retrieves multiple recipes to perform its tasks. The PLCcommunicates over a network to allow real time monitoring of productionthroughput, preventive maintenance, and remote diagnostics management.The web feeder provides an in and out-feed to a piercing chain toprovide safe rapid recovery from both machine malfunctions and rollchange out. A heater provides a heat zone over the web feeder. The heatzone further comprises a plurality of in-line individually controlledmodular ceramic heaters. The load station comprises an opposing dualplatform to allow continuous rotary introduction of unique molds to webwithout interruption to the process. The load station allowssimultaneous loading of the next mold during the forming process. Theforming station allows continuous introduction and removal of new uniquemold to be thermoformed at each cycle. The forming station furthercomprises a pressure/vacuum chamber and wherein the pressure/vacuumchamber is first sealed on the web to allow pre-forming. The mold isintroduced to the pre-formed web and simultaneously the vacuum andpressure are applied to form the material on the mold. The material isblown in a first direction over the mold and then blown in an oppositedirection to deposit over the mold. Each mold is formed with a 2D datamatrix code containing unique identification of the mold. A machinevision module performs a data acquisition from a multi-dimensionalmatrix code and reports it to a laser marking system. The vision modulecomprises a camera and a light ring set up vertically over the station.The chamber is opened the load platform is withdrawn and the mold isretained in the web and transferred to the machine vision module. Thelaser marker is a diode pump laser with marking head, standard markingand targeting software and laser parameters. The PLC and PC controllerprovide HMI safety access and the laser system meets CDRH certificationby manufacturer.

In one embodiment, an integrated thermo-former and laser marker devicesupports mass customization manufacturing of dental appliances. Thesystem includes in-line integration of: Incremental Web precision feedand speed control; multiple heat zone control and closed loop monitoringcapable of ramping material to forming temperature; and continuous feedrotary SLA mold introduction to the web forming process. The thermoformprocess incorporates the web, a unique mold every cycle, pre-forming theweb, pressure and vacuum forming, and mold retention in the web. Amachine vision station acquires data that identifies each unit andcommunicates the data to the laser marker. The laser marker retrievesunit ID data over a network and performs automated targeting of amarking zone. A die cutter automatically removes a predetermined area ofusable web and discharges the unit to an automated material handlingequipment. A Web out feed take-up spool is used to manage wastematerial.

In one embodiment, a programmable logic controller (PLC) manageselectrical and pneumatic I/O for the web feed, heat zone, rotary SLAfeed, forming, machine vision and die cutting functions. The PLC canstore and retrieve multiple recipes. The PLC also communicates usingnetwork connectivity to allow real time monitoring of productionthroughput, preventive maintenance, remote diagnostics management anddowntime.

In one aspect, the web feed is capable of handling a pliant materialsuch as plastic. The web feed interacts with a payout device thatcontrols environmental and static control to meet the requirements forthe material. An In and Out-feed provides a piercing chain mechanism toprovide a rapid roll change out.

In another embodiment, in-line individually controlled modular ceramicheaters are used in the heat zone. Ceramic heaters with controlled zonesare used to achieve required cycle times. An opposing dual platform loadstation allows continuous rotary introduction of unique molds to the webwithout interruption of the process. This will allow simultaneousloading of the next mold during the forming process. The forming stationallows continuous introduction and removal of new unique mold to bethermoformed at each cycle. The pressure/vacuum chamber is first sealedon the web allowing pre-forming to occur. The mold is then introduced tothe pre-formed web, and simultaneously the vacuum and pressure areapplied to form the material on the mold. As the chamber is opened, theload platform is withdrawn, and the mold is retained in the web andtransferred to the machine vision station.

Every unit, in this case a stereolithography apparatus (SLA) mold, isbuilt with a 2D data matrix code containing unique identification.Machine vision performs a data acquisition from that data matrix codeand reports the data to the Laser Marking station. The vision systemincludes a digital camera and light ring set up vertically over thestation. During laser marking, a computer-controlled laser with markinghead receives data from the machine vision system. The laser machineinterlocks to provide safe access for maintenance, minor repairs oradjustments to equipment.

FIG. 6 shows an exemplary process to fabricate units usingmass-customization. First, rolled thermoplastic material is retrievedfrom a storage device 111. The rolled material is controlled anddelivered to a spooler 113. At this stage, the material is in acontrolled environment that keeps temperature, moisture and staticelectricity conditions, among others, within a predetermined tolerance(115). Next, the rolled material is provided to a web feed system 117.Incoming material is precision aligned, captured and fed (118). Thematerial is also provided to a piercing chain for incremental sequencingcontrol (120). The web fed thermoplastic material is provided to a heatzone where the material is heated in one embodiment (112). The materialis heated to a forming temperature (124). A ramp heating system is usedwith controllable heat elements (126).

The molds 90 are transferred to a load station (128). The molds arefirst placed on a load station for introduction to a forming station(130). The molds can be manually loaded (132) or can be automaticallyloaded (134). Next, the thermoplastic material is formed over one ormore molds (137). The heated material is pressure and vacuum formed overthe molds (138). In a pre-forming operation, material is blown into adome shape to provide a uniform thickness (140). The mold is introducedinto the pre-formed dome shape (142), and pressure and vacuum is appliedto form the unit (144).

The formed material includes part identification (ID), which is detectedby machine vision using a camera and light ring (150). A 2D ID code isread and a corresponding file for the unit is retrieved over the network(152). The 2D data matrix bar code is formed directly on the unit (154).A hot-stamp contrast of the 2D code is performed to improve readability(156). The output of the vision camera with light ring is communicatedfor marking purposes (158).

The identification information is provided to the laser marker (160),where the units are encoded. In the case of dental appliances, patientreadable information is marked on each appliance (162). The data filefor one dental embodiment includes patient ID, stage, and overcorrectionID, for example (164). A laser then burns the patient readableinformation on the appliance (166). FIG. 7 shows an exemplary dentalappliance during manufacturing at operation 166. Subsequently, the unitsare die cut and trimmed (170). Unused material is off-loaded from thesystem (172).

After trimming, the aligner 136 is provided to a tumbler. In oneembodiment, the tumbler is a centrifugal barrel finishing tumbler. Inone embodiment, a turret with four barrels mounted parallel to its axissuch as the CPC2500 from United Finishing System Inc. (Baldwin Park,Calif.) is used. Small pebbles are placed therein to polish the parts.In one embodiment, the pebbles are triangular-shaped pebbles. When theturret rotates, the barrels are driven at a 1:1 ratio in the oppositedirection of rotation maintaining a stationary orbit around the centerhub (similar to the action of a Ferris wheel). The resultinggravitational force generates friction on the contents within thebarrel. The parts are forced through the media in a cyclonic action todeburr, refine and polish at high speed. Aggressive forces within thebarrel are manipulated by adjusting the turret's rotational speed andthe barrel's media level. This gives operators the control necessary toeliminate damage on soft parts such as the aligners 136.

After tumbling to remove sharp edges, the aligner 136 is provided intoan ultrasonic washer which disinfects and heat-dries the aligners. Avariety of ultrasonic washers can be used as ultrasonic cavitation isable to clean right down to the surface of a part and beyond. It is alsoable to reach internal areas which are not accessible using othercleaning means including spray and mechanical agitation. The forcefulnature of ultrasonic energy provides the physical “push” required tobreak the mechanical curd ionic bonds that hold very small particles tosurfaces. Consistent cleanliness is assured by the ability of ultrasonicenergy to reach any surface in contact with the cleaning liquid, whichin one embodiment is soap/water combination.

Next, the aligners 136 are packed, and labels are applied to thepackages. The resulting packages are then shipped to customers.Typically the appliances are to be worn in a particular sequence toprovide desired treatment, such as a progressive movement of teeththrough a variety of arrangements to a final desired arrangement. In oneembodiment, a system of dental appliances is provided, comprising aplurality of dental appliances wherein at least some of the pluralityinclude non-numeric indicia designating all order in which each of theat least some of the plurality are to be worn by a patient to providedental treatment. Typically, each of the plurality of dental appliancescomprises a polymeric shell having cavities shaped to receive andresiliently reposition teeth from one arrangement to a successivearrangement. In some embodiments, each of the polymeric shells has atleast one terminal tooth cavity, and the indicia comprise a terminaltooth cavity of differing length in each of the polymeric shells. Inother embodiments, each of the polymeric shells has a height, and theindicia comprise a different height in each of the polymeric shells. Instill other embodiments, the indicia comprise one or more cutouts sothat each polymeric shell has a different cutout pattern. Sometimes thecutout comprises a notch in an edge of the appliance. In yet otherembodiments, the indicia comprise a color wherein each appliance has adifferent color. The color of the appliances may have the same hue andvary by intensity, for example. The color may comprise a dissolvabledye. Or, the system may further comprise a wrapper removably attachableto each of the appliances, wherein each wrapper has the color. Inanother embodiment, a system of packaged dental appliances is providedcomprising a plurality of packages each containing a dental appliance,wherein the plurality of packages are joined in a continuous chaindesignating an order in which each of the dental appliances are to beworn by a patient to provide dental treatment. In some instances, thepackages are each joined by a perforation wherein the packages can beseparated by breaking the perforation. In other instances, the packagesare joined by, for example, a heat seal. Further, the system may includea marking on a package at an end of the chain indicating the dentalappliance to be worn first. Again, each of the plurality of dentalappliances may comprise a polymeric shell having cavities shaped toreceive and resiliently reposition teeth from one arrangement to asuccessive arrangement. In yet other embodiments, a system of dentalappliances is provided comprising a plurality of dental appliances to beworn by a patient to provide dental treatment, and a framework, whereineach of the plurality of dental appliances is removably attached to aportion of the framework. In some embodiments, each of the plurality ofdental appliances comprises a polymeric shell having cavities shaped toreceive and resiliently reposition teeth from one arrangement to asuccessive arrangement. Further, the system may comprise at least onemarking on the framework indicating the order in which the appliancesare to be worn by a patient. In still another embodiment, a plurality ofpackages are produced wherein each of the packages includes a polymericshell having cavities shaped to receive and resiliently reposition teethfrom one arrangement to a successive arrangement, the plurality ofpackage including a first package containing a first shell to be worn bythe patient to reposition the teeth from the one arrangement to thesuccessive arrangement and a second package containing a second shell tobe worn by the patient to reposition the teeth from the successivearrangement to another successive arrangement. The first package can beprovided to the patient at a designated time though a remote deliverysystem, and delivering the second package to the patient at a laterdesignated time through the remote delivery system. In most embodiments,the remote delivery system comprises a mail delivery system.

FIG. 8 shows an exemplary dental appliance during use. A plurality ofincremental position adjustment appliances, one of which is shown inFIG. 8, are used to effect incremental repositioning of individualteeth. In a broadest sense, the system can employ any of the knownpositioners, retainers, or other removable appliances which are knownfor finishing and maintaining teeth positions in connection withconventional orthodontic treatment. A plurality of such appliancesintended to be worn by a patient successively in order to achieve thegradual tooth repositioning as described herein. The appliance of FIG. 8is a polymeric shell having a cavity shaped to receive and resiliencyreposition teeth from one tooth arrangement to a successive tootharrangement. The polymeric shell will preferably, but not necessarily,fit over all teeth present in the upper or lower jaw. Often, onlycertain one(s) of the teeth will be repositioned while others of theteeth will provide a base or anchor region for holding the repositioningappliance in place as it applies the resilient repositioning forceagainst the tooth or teeth to be repositioned. In complex cases,however, many or most of the teeth will be repositioned at some pointduring the treatment. In such cases, the teeth which are moved can alsoserve as a base or anchor region for holding the repositioningappliance. Additionally, the gums and/or the palette can serve as ananchor region, thus allowing all or nearly all of the teeth to berepositioned simultaneously.

The manner of usage and operation of the invention described above beingreadily apparent from the above disclosure, no further discussionrelative to the manner of usage and operation of the invention shall beprovided. With respect to the above description, it is to be understoodthat the optimum dimensional relationships for the parts of theinvention, as well as variations in size, materials, shape, form,function, and manner of operation, assembly, and use, and equivalents ofall the foregoing, are apparent to one skilled in the art. Suchequivalents are intended to be encompassed by the present invention.Therefore, the foregoing is considered as illustrative only of theprinciples of the invention. Further, since numerous modifications andchanges will be readily apparent to those skilled in the art, it is notintended to limit the invention to the exact construction and operationshovel and described, but to encompass all suitable modifications andequivalents within the scope of the invention. The scope of theinvention is indicated by the appended claims rather than by theforegoing description.

1-48. (canceled)
 49. A system for forming molded items fromthermoplastic workpieces, comprising: a workpiece heating mechanismoperable to heat a series of thermoplastic workpieces; a workpiecemanipulator operable to move each workpiece sequentially from theheating mechanism to a workpiece operation chamber; a plurality ofmolds, each single mold in the plurality of molds representing a uniqueshape; a plug in the workpiece operation chamber that is cooperativelyengageable with each of the molds; and a mold manipulator operable tosequentially move the plurality of molds to the workpiece operationchamber for engagement with the plug therein; the workpiece manipulatorand the mold manipulator being operable to position each workpiece inthe workpiece operation chamber between a single mold and the plug sothat each workpiece is formed into a uniquely shaped molded item throughthe cooperative engagement of the single mold and the plug.
 50. Thesystem of claim 49, further comprising a workpiece introduction systemoperable to introduce the series of workpieces sequentially into theworkpiece heating mechanism.
 51. The system of claim 50, wherein theworkpiece introduction system is an inline system.
 52. The system ofclaim 50, wherein the workpiece introduction system is a rotary turretsystem.
 53. The system of claim 49, wherein the mold manipulator systemis a rotary turret system.
 54. The system of claim 50, wherein theworkpiece introduction system includes a cutter that is operable to formthe series of workpieces from a roll of thermoplastic material.
 55. Thesystem of claim 49, further comprising a mold preparation chamber, andwherein the mold manipulator system is operable to move each of themolds from the mold preparation chamber to the workpiece operationchamber.
 56. The system of claim 55, wherein the mold preparationchamber includes the mold heating mechanism.
 57. The system of claim 49,further comprising a laser-marking system operable to mark each moldeditem following its removal from the workpiece operation chamber.
 58. Thesystem of claim 49, further comprising a trimming system operable totrim each molded item following its removal from the workpiece operationchamber.
 59. The system of claim 58, wherein the trimming systemincludes a multiple-axis CNC system.
 60. The system of claim 49, whereinthe molded items are uniquely shaped dental aligners.
 61. The system ofclaim 49, wherein the plug is one of a series of plugs, each of which isconfigured for cooperation with a corresponding mold to ensure that theworkpiece is pulled over the mold.
 62. A system for forming molded itemsfrom thermoplastic workpieces, comprising: a workpiece heating mechanismoperable to heat a series of thermoplastic workpieces; a workpieceoperation chamber; a workpiece manipulator operable to move the seriesof workpieces sequentially from the heating mechanism to the workpieceoperation chamber; a plurality of molds, each single mold in theplurality of molds representing a unique shape; and a mold manipulatoroperable to sequentially move the plurality of molds to the workpieceoperation chamber; the workpiece manipulator and the mold manipulatorbeing operable to deliver each single workpiece in the series ofworkpieces and each single mold in the plurality of molds substantiallysimultaneously to the workpiece operation chamber and to present thesingle workpiece to the single mold so that the single workpiece isformed into a uniquely shaped molded item.
 63. The system of claim 62,further comprising a workpiece introduction system operable to introducethe series of workpieces sequentially into the workpiece heatingmechanism.
 64. The system of claim 63, wherein the workpieceintroduction system is an inline system.
 65. The system of claim 63,wherein the workpiece introduction system is a rotary turret system. 66.The system of claim 62, wherein the mold manipulator system is a rotaryturret system.
 67. The system of claim 63, wherein the workpieceintroduction system includes a cutter that is operable to form theseries of workpieces from a roll of thermoplastic material.
 68. Thesystem of claim 62, further comprising a mold preparation chamber, andwherein the mold manipulator system is operable to move each of themolds from the mold preparation chamber to the workpiece operationchamber.
 69. The system of claim 68, wherein the mold preparationchamber includes the mold heating mechanism.
 70. The system of claim 62,further comprising a laser-marking system operable to mark each moldeditem following its removal from the workpiece operation chamber.
 71. Thesystem of claim 62, further comprising a trimming system operable totrim each molded item following its removal from the workpiece operationchamber.
 72. The system of claim 71, wherein the trimming systemincludes a multiple-axis CNC system.
 73. The system of claim 62, whereinthe molded items are uniquely shaped dental aligners.
 74. The system ofclaim 62, wherein the workpiece operation chamber is operable to apply avacuum to form the single workpiece into the unique mold item.